High-Capacity Janus Aminobenzene-Graphene Anode for Sodium-Ion Batteries Characterized via Machine-Learning Force Fields

Forum topic · 小凯 · 2026-03-25

Summary

Sodium-ion batteries need anodes combining high capacity, low operating voltage, fast Na-ion transport, and mechanical stability, which conventional anodes struggle to deliver. In an arXiv preprint (2603.22254), researchers led by Claudia Islas-Vargas and Huziel E. Sauceda used the SpookyNet machine-learning force field together with all-electron density-functional theory to characterize sodium storage in aminobenzene-functionalized Janus graphene (Na_xAB) at room temperature. Simulations across the full state of charge revealed a three-stage storage mechanism: site-specific adsorption at aminobenzene groups, formation of Na_n@AB_m structures, and interlayer gallery filling—a mechanism distinct from the pore-, interlayer-, and defect-controlled multi-stage behavior of hard carbon. The resulting open-circuit voltage curve shows an extended low-voltage plateau at 0.15 V vs. Na/Na+, with an estimated gravimetric capacity of ~400 mAh g-1, negligible volume change, and a sodium diffusion coefficient of ~10^-6 cm^2 s-1, two to three orders of magnitude faster than hard carbon. The work establishes Janus aminobenzene-graphene as a promising structurally well-defined high-capacity anode and demonstrates the power of MLFF-based simulations for electrode material characterization.

Paper Overview

Field: Machine Learning for Materials Science Authors: Claudia Islas-Vargas, L. Ricardo Montoya, Carlos A. Vital-José, Oliver T. Unke, Klaus-Robert Müller, Huziel E. Sauceda Published: 2026-03-23 arXiv: 2603.22254

Abstract (English)

Sodium-ion batteries require anodes that combine high capacity, low operating voltage, fast Na-ion transport, and mechanical stability, which conventional anodes struggle to deliver. Here, we use the SpookyNet machine-learning force field (MLFF) together with all-electron density-functional theory calculations to characterize Na storage in aminobenzene-functionalized Janus graphene (Na_xAB) at room-temperature. Simulations across state of charge reveal a three-stage storage mechanism—site-specific adsorption at aminobenzene groups and Na_n@AB_m structure formation, followed by interlayer gallery filling—contrasting the multi-stage pore-, graphite-interlayer-, and defect-controlled behavior in hard carbon. This leads to an OCV profile with an extended low-voltage plateau of 0.15 V vs. Na/Na+, an estimated gravimetric capacity of ~400 mAh g-1, negligible volume change, and a Na diffusion coefficient of ~10^-6 cm^2 s-1, which is 2–3 orders of magnitude higher than in hard carbon. Our results establish Janus aminobenzene-graphene as a promising structurally well-defined high-capacity anode for sodium-ion batteries and demonstrate the power of MLFF-based simulations for characterizing electrode materials.

Key Findings

Three-stage Na storage mechanism: (1) site-specific adsorption at aminobenzene groups, (2) Na_n@AB_m structure formation, (3) interlayer gallery filling.
Differs fundamentally from the multi-stage pore-, graphite-interlayer-, and defect-controlled storage behavior of hard carbon.
Extended low-voltage plateau at 0.15 V vs. Na/Na+.
Estimated capacity of ~400 mAh g-1 with negligible volume change.
Na diffusion coefficient of ~10^-6 cm^2 s-1, 2–3 orders of magnitude faster than hard carbon.
Demonstrates MLFF (SpookyNet) simulations as a powerful tool for electrode characterization.

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